Action potential firing properties of DCN neurons.
a Example traces from cell-attached voltage-clamp recordings. With the exception of Gly-I cells, all cell types fire regularly with a frequency much greater than 0.1 Hz.
b Example traces showing voltage responses to depolarizing current injections (1-s, 1.5 pA/pF for GADnL, GADnS, and GAD+; 0.9, 1.5, and 2.4 pA/pF for Gly-I). Note the higher firing rheobase in Gly-I cell.
c Peak-aligned, averaged action potentials; width of the trace represents ± SEM.
Single arrowheads mark fast afterhyperpolarization,
double arrowheads mark slow afterhyperpolarization.
d Example traces showing voltage responses to hyperpolarizing current injections (1-s, −1.5 pA/pF). GADnL, GADnS, and GAD+ cells displayed I
h-indicating voltage sags (
single arrowhead) and pronounced rebound depolarization and associated firing (
double arrowhead).
e Statistical summaries of key electrophysiological parameters.
i Spontaneous firing frequency under cell-attached conditions. Note that Gly-I cells did not spontaneously fire continuously.
ii Action potential half width, measured from repetitively fired action potentials at room temperature (RT; 24°C).
iii Duration of rebound depolarization and associated spiking at half-amplitude at RT. Note that Gly-I cells never fired spikes on rebound.
iv Mean firing frequency during a step depolarization versus injected current. Note that in order to enable meaningful comparison of I-F curves in cells of significantly different sizes, the injected current is given in relative units of pA/pF.
v Spiking frequency adaptation during a step depolarization that evoked ~40 Hz (GADnL, GADnS, and GAD+) or ~30 Hz (Gly-I) firing. Data in
a–
d are modified from [
11] and [
12]. Panels from
e were modified from the following sources:
i and
iii from [
11],
ii from [
48], and
iv and
v from a combination of [
11] with [
48].
Asterisks denote statistical significance: *
p < 0.05, **
p < 0.01, and ***
p < 0.001; non-significant differences are left unlabeled for visual clarity